Rozhen Observation Calendar

Which nights are best for a target over the coming weeks. The astronomy mark (darkness × altitude × Moon) is computed for every night; the weather and the overall mark exist only where Open-Meteo has a forecast (the next four days) or ERA5 history (past nights) — the rest is honestly blank.

Best nights for North America Nebula: 08-17 (100), 08-18 (100), 08-19 (100), 08-20 (100), 08-21 (100) — by astronomy; check the weather when the night is within four days.

2045-08-17astronomy score per night — click a bar for that night2045-09-15

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2045-08-17 Thu	100	—	unknown	22:05–04:50 (good, 6.75 h)	87.2° 00:35	6.78	34%	111.6°
2045-08-18 Fri	100	—	unknown	22:00–04:55 (good, 6.92 h)	87.2° 00:30	6.84	44%	105.1°
2045-08-19 Sat	100	—	unknown	22:00–04:55 (good, 6.92 h)	87.2° 00:25	6.9	55%	98.1°
2045-08-20 Sun	100	—	unknown	22:00–04:55 (good, 6.92 h)	87.2° 00:25	6.95	64%	91.1°
2045-08-21 Mon	100	—	unknown	21:55–04:55 (good, 7.0 h)	87.2° 00:20	7.01	74%	84.2°
2045-08-22 Tue	100	—	unknown	21:55–05:00 (good, 7.08 h)	87.2° 00:15	7.07	82%	77.5°
2045-08-23 Wed	98	—	unknown	21:55–05:00 (good, 7.08 h)	87.2° 00:10	7.13	88%	71.4°
2045-08-24 Thu	90	—	unknown	21:50–05:00 (good, 7.17 h)	87.2° 00:05	7.18	94%	65.9°
2045-08-25 Fri	62	—	unknown	02:10–05:05 (good, 2.92 h)	87.2° 00:05	7.24	98%	61.4°
2045-08-26 Sat	60	—	unknown	21:10–05:05 (marginal, 7.92 h)	87.2° 00:00	7.3	100%	58.0°
2045-08-27 Sun	60	—	unknown	21:10–05:05 (marginal, 7.92 h)	87.2° 23:55	7.35	100%	56.0°
2045-08-28 Mon	62	—	unknown	21:45–22:05 (good, 0.33 h)	87.2° 23:50	7.41	98%	55.7°
2045-08-29 Tue	65	—	unknown	21:40–22:45 (good, 1.08 h)	87.1° 23:50	7.47	95%	57.1°
2045-08-30 Wed	70	—	unknown	21:40–23:50 (good, 2.17 h)	87.2° 23:45	7.52	90%	60.1°
2045-08-31 Thu	76	—	unknown	21:35–01:45 (good, 4.17 h)	87.2° 23:40	7.58	83%	64.5°
2045-09-01 Fri	100	—	unknown	21:35–03:20 (good, 5.75 h)	87.2° 23:35	7.63	75%	70.1°
2045-09-02 Sat	100	—	unknown	21:35–04:35 (good, 7.0 h)	87.2° 23:30	7.69	66%	76.6°
2045-09-03 Sun	100	—	unknown	21:30–05:15 (good, 7.75 h)	87.2° 23:30	7.74	55%	83.7°
2045-09-04 Mon	100	—	unknown	21:30–05:15 (good, 7.75 h)	87.2° 23:25	7.8	44%	91.2°
2045-09-05 Tue	100	—	unknown	21:25–05:20 (good, 7.92 h)	87.2° 23:20	7.86	34%	98.9°
2045-09-06 Wed	100	—	unknown	21:25–05:20 (good, 7.92 h)	87.2° 23:15	7.91	23%	106.5°
2045-09-07 Thu	100	—	unknown	21:25–05:20 (good, 7.92 h)	87.2° 23:10	7.96	14%	113.4°
2045-09-08 Fri	100	—	unknown	21:20–05:20 (good, 8.0 h)	87.2° 23:10	8.02	7%	119.1°
2045-09-09 Sat	100	—	unknown	21:20–05:25 (good, 8.08 h)	87.2° 23:05	8.07	2%	123.0°
2045-09-10 Sun	100	—	unknown	21:15–05:20 (good, 8.08 h)	87.2° 23:00	8.13	0%	124.3°
2045-09-11 Mon	100	—	unknown	21:15–05:15 (good, 8.0 h)	87.2° 22:55	8.18	1%	123.0°
2045-09-12 Tue	100	—	unknown	21:15–05:15 (good, 8.0 h)	87.1° 22:55	8.23	5%	119.3°
2045-09-13 Wed	100	—	unknown	21:10–05:10 (good, 8.0 h)	87.2° 22:50	8.29	11%	113.9°
2045-09-14 Thu	100	—	unknown	21:10–05:05 (good, 7.92 h)	87.2° 22:45	8.34	20%	107.4°
2045-09-15 Fri	100	—	unknown	21:05–05:00 (good, 7.92 h)	87.2° 22:40	8.39	29%	100.4°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2045-08-17&days=30"
curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&days=30&format=csv" -o m31-calendar.csv

One row per night: score_astronomy always, score_weather / score only where a forecast or history exists (null otherwise, with weather_source saying which), best window, dark hours, Moon illumination and separation, transit. 7–60 nights. Errors: 400 with invalid_date or target_unresolved. Results are cached for six hours; calculation version 2026-10-10.1.